The present invention relates to controls for self-propelled, walk-behind implements and more specifically relates to such controls designed to require the operator to go through two stages or two steps of lever actuation to accomplish engagement of each of the traction and tool drives of the implement.
A known two-stage control for a lawn mower is illustrated and described in U.S. patent application Ser. No. 005,133 filed by John J. Hoch on Jan. 22, 1979 and entitled Two-stage Deadman Control for Walk-Behind Mower filed by the same assignee. The control disclosed in the Hoch application includes a traction drive control lever biased toward a normal clutch-disengage position and movable to a clutch-engage position in which it is held by a deadman control lever after the latter is moved, against the force of a biasing spring, from a normally released position to an actuated position wherein it is gripped against the mower guide handle. The disclosure alludes to a mower having a blade drive control clutch operated by the deadman control lever such that it is selectively engageable independently of the traction drive clutch. This latter operation is not satisfactory, however, since it is just as important from a safety standpoint to protect against inadvertent operation of the blade drive as it is to protect against inadvertent operation of the traction drive.